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TRANSPORT(5) TRANSPORT(5)
<b>NAME</b>
transport - Postfix transport table format
<b>SYNOPSIS</b><b>postmap /etc/postfix/transport</b><b>postmap -q "</b><i>string</i><b>" /etc/postfix/transport</b><b>postmap -q - /etc/postfix/transport</b>&lt;<i>inputfile</i><b>DESCRIPTION</b>
The optional <a href="transport.5.html"><b>transport</b>(5)</a> table specifies a mapping from
email addresses to message delivery transports and next-
hop destinations. Message delivery transports such as
<b>local</b> or <b>smtp</b> are defined in the <a href="master.5.html"><b>master.cf</b></a> file, and next-
hop destinations are typically hosts or domain names. The
table is searched by the <a href="trivial-rewrite.8.html"><b>trivial-rewrite</b>(8)</a> daemon.
This mapping overrides the default <i>transport</i>:<i>nexthop</i>
selection that is built into Postfix:
<b><a href="postconf.5.html#local_transport">local_transport</a> (default: <a href="local.8.html">local</a>:$<a href="postconf.5.html#myhostname">myhostname</a>)</b>
This is the default for final delivery to domains
listed with <b><a href="postconf.5.html#mydestination">mydestination</a></b>, and for [<i>ipaddress</i>] des-
tinations that match <b>$<a href="postconf.5.html#inet_interfaces">inet_interfaces</a></b> or
<b>$<a href="postconf.5.html#proxy_interfaces">proxy_interfaces</a></b>. The default <i>nexthop</i> destination
is the MTA hostname.
<b><a href="postconf.5.html#virtual_transport">virtual_transport</a> (default: <a href="virtual.8.html">virtual</a>:)</b>
This is the default for final delivery to domains
listed with <b><a href="postconf.5.html#virtual_mailbox_domains">virtual_mailbox_domains</a></b>. The default
<i>nexthop</i> destination is the recipient domain.
<b><a href="postconf.5.html#relay_transport">relay_transport</a> (default: relay:)</b>
This is the default for remote delivery to domains
listed with <b><a href="postconf.5.html#relay_domains">relay_domains</a></b>. In order of decreasing
precedence, the <i>nexthop</i> destination is taken from
<b><a href="postconf.5.html#relay_transport">relay_transport</a></b>, <b><a href="postconf.5.html#sender_dependent_relayhost_maps">sender_dependent_relayhost_maps</a></b>,
<b><a href="postconf.5.html#relayhost">relayhost</a></b>, or from the recipient domain.
<b><a href="postconf.5.html#default_transport">default_transport</a> (default: <a href="smtp.8.html">smtp</a>:)</b>
This is the default for remote delivery to other
destinations. In order of decreasing precedence,
the <i>nexthop</i> destination is taken from <b><a href="postconf.5.html#sender_dependent_default_transport_maps">sender_depen</a>-</b><b><a href="postconf.5.html#sender_dependent_default_transport_maps">dent_default_transport_maps</a>, <a href="postconf.5.html#default_transport">default_transport</a></b>,
<b><a href="postconf.5.html#sender_dependent_relayhost_maps">sender_dependent_relayhost_maps</a></b>, <b><a href="postconf.5.html#relayhost">relayhost</a></b>, or from
the recipient domain.
Normally, the <a href="transport.5.html"><b>transport</b>(5)</a> table is specified as a text
file that serves as input to the <a href="postmap.1.html"><b>postmap</b>(1)</a> command. The
result, an indexed file in <b>dbm</b> or <b>db</b> format, is used for
fast searching by the mail system. Execute the command
"<b>postmap /etc/postfix/transport</b>" to rebuild an indexed
file after changing the corresponding transport table.
When the table is provided via other means such as NIS,
LDAP or SQL, the same lookups are done as for ordinary
indexed files.
Alternatively, the table can be provided as a regular-
expression map where patterns are given as regular expres-
sions, or lookups can be directed to TCP-based server. In
those case, the lookups are done in a slightly different
way as described below under "REGULAR EXPRESSION TABLES"
or "TCP-BASED TABLES".
<b>CASE FOLDING</b>
The search string is folded to lowercase before database
lookup. As of Postfix 2.3, the search string is not case
folded with database types such as <a href="regexp_table.5.html">regexp</a>: or <a href="pcre_table.5.html">pcre</a>: whose
lookup fields can match both upper and lower case.
<b>TABLE FORMAT</b>
The input format for the <a href="postmap.1.html"><b>postmap</b>(1)</a> command is as follows:
<i>pattern result</i>
When <i>pattern</i> matches the recipient address or
domain, use the corresponding <i>result</i>.
blank lines and comments
Empty lines and whitespace-only lines are ignored,
as are lines whose first non-whitespace character
is a `#'.
multi-line text
A logical line starts with non-whitespace text. A
line that starts with whitespace continues a logi-
cal line.
The <i>pattern</i> specifies an email address, a domain name, or
a domain name hierarchy, as described in section "TABLE
LOOKUP".
The <i>result</i> is of the form <i>transport:nexthop</i> and specifies
how or where to deliver mail. This is described in section
"RESULT FORMAT".
<b>TABLE SEARCH ORDER</b>
With lookups from indexed files such as DB or DBM, or from
networked tables such as NIS, LDAP or SQL, patterns are
tried in the order as listed below:
<i>user+extension@domain transport</i>:<i>nexthop</i>
Deliver mail for <i>user+extension@domain</i> through
<i>transport</i> to <i>nexthop</i>.
<i>user@domain transport</i>:<i>nexthop</i>
Deliver mail for <i>user@domain</i> through <i>transport</i> to
<i>nexthop</i>.
<i>domain transport</i>:<i>nexthop</i>
Deliver mail for <i>domain</i> through <i>transport</i> to <i>nex-</i><i>thop</i>.
<i>.domain transport</i>:<i>nexthop</i>
Deliver mail for any subdomain of <i>domain</i> through
<i>transport</i> to <i>nexthop</i>. This applies only when the
string <b><a href="postconf.5.html#transport_maps">transport_maps</a></b> is not listed in the <b><a href="postconf.5.html#parent_domain_matches_subdomains">par</a>-</b><b><a href="postconf.5.html#parent_domain_matches_subdomains">ent_domain_matches_subdomains</a></b> configuration set-
ting. Otherwise, a domain name matches itself and
its subdomains.
<b>*</b><i>transport</i>:<i>nexthop</i>
The special pattern <b>*</b> represents any address (i.e.
it functions as the wild-card pattern, and is
unique to Postfix transport tables).
Note 1: the null recipient address is looked up as
<b>$<a href="postconf.5.html#empty_address_recipient">empty_address_recipient</a></b>@<b>$<a href="postconf.5.html#myhostname">myhostname</a></b> (default: mailer-dae-
mon@hostname).
Note 2: <i>user@domain</i> or <i>user+extension@domain</i> lookup is
available in Postfix 2.0 and later.
<b>RESULT FORMAT</b>
The lookup result is of the form <i>transport</i><b>:</b><i>nexthop</i>. The
<i>transport</i> field specifies a mail delivery transport such
as <b>smtp</b> or <b>local</b>. The <i>nexthop</i> field specifies where and
how to deliver mail.
The transport field specifies the name of a mail delivery
transport (the first name of a mail delivery service entry
in the Postfix <a href="master.5.html"><b>master.cf</b></a> file).
The interpretation of the nexthop field is transport
dependent. In the case of SMTP, specify a service on a
non-default port as <i>host</i>:<i>service</i>, and disable MX (mail
exchanger) DNS lookups with [<i>host</i>] or [<i>host</i>]:<i>port</i>. The []
form is required when you specify an IP address instead of
a hostname.
A null <i>transport</i> and null <i>nexthop</i> result means "do not
change": use the delivery transport and nexthop informa-
tion that would be used when the entire transport table
did not exist.
A non-null <i>transport</i> field with a null <i>nexthop</i> field
resets the nexthop information to the recipient domain.
A null <i>transport</i> field with non-null <i>nexthop</i> field does
not modify the transport information.
<b>EXAMPLES</b>
In order to deliver internal mail directly, while using a
mail relay for all other mail, specify a null entry for
internal destinations (do not change the delivery trans-
port or the nexthop information) and specify a wildcard
for all other destinations.
<b>my.domain :</b><b>.my.domain :</b><b>* <a href="smtp.8.html">smtp</a>:outbound-relay.my.domain</b>
In order to send mail for <b>example.com</b> and its subdomains
via the <b>uucp</b> transport to the UUCP host named <b>example</b>:
<b>example.com uucp:example</b><b>.example.com uucp:example</b>
When no nexthop host name is specified, the destination
domain name is used instead. For example, the following
directs mail for <i>user</i>@<b>example.com</b> via the <b>slow</b> transport
to a mail exchanger for <b>example.com</b>. The <b>slow</b> transport
could be configured to run at most one delivery process at
a time:
<b>example.com slow:</b>
When no transport is specified, Postfix uses the transport
that matches the address domain class (see DESCRIPTION
above). The following sends all mail for <b>example.com</b> and
its subdomains to host <b>gateway.example.com</b>:
<b>example.com :[gateway.example.com]</b><b>.example.com :[gateway.example.com]</b>
In the above example, the [] suppress MX lookups. This
prevents mail routing loops when your machine is primary
MX host for <b>example.com</b>.
In the case of delivery via SMTP, one may specify <i>host-</i><i>name</i>:<i>service</i> instead of just a host:
<b>example.com <a href="smtp.8.html">smtp</a>:bar.example:2025</b>
This directs mail for <i>user</i>@<b>example.com</b> to host <b>bar.example</b>
port <b>2025</b>. Instead of a numerical port a symbolic name may
be used. Specify [] around the hostname if MX lookups must
be disabled.
The error mailer can be used to bounce mail:
<b>.example.com <a href="error.8.html">error</a>:mail for *.example.com is not deliverable</b>
This causes all mail for <i>user</i>@<i>anything</i><b>.example.com</b> to be
bounced.
<b>REGULAR EXPRESSION TABLES</b>
This section describes how the table lookups change when
the table is given in the form of regular expressions. For
a description of regular expression lookup table syntax,
see <a href="regexp_table.5.html"><b>regexp_table</b>(5)</a> or <a href="pcre_table.5.html"><b>pcre_table</b>(5)</a>.
Each pattern is a regular expression that is applied to
the entire address being looked up. Thus,
<i>some.domain.hierarchy</i> is not looked up via its parent
domains, nor is <i>user+foo@domain</i> looked up as <i>user@domain</i>.
Patterns are applied in the order as specified in the ta-
ble, until a pattern is found that matches the search
string.
The <a href="trivial-rewrite.8.html"><b>trivial-rewrite</b>(8)</a> server disallows regular expression
substitution of $1 etc. in regular expression lookup
tables, because that could open a security hole (Postfix
version 2.3 and later).
<b>TCP-BASED TABLES</b>
This section describes how the table lookups change when
lookups are directed to a TCP-based server. For a descrip-
tion of the TCP client/server lookup protocol, see <a href="tcp_table.5.html"><b>tcp_ta-</b></a><a href="tcp_table.5.html"><b>ble</b>(5)</a>. This feature is not available up to and including
Postfix version 2.4.
Each lookup operation uses the entire recipient address
once. Thus, <i>some.domain.hierarchy</i> is not looked up via
its parent domains, nor is <i>user+foo@domain</i> looked up as
<i>user@domain</i>.
Results are the same as with indexed file lookups.
<b>CONFIGURATION PARAMETERS</b>
The following <a href="postconf.5.html"><b>main.cf</b></a> parameters are especially relevant.
The text below provides only a parameter summary. See
<a href="postconf.5.html"><b>postconf</b>(5)</a> for more details including examples.
<b><a href="postconf.5.html#empty_address_recipient">empty_address_recipient</a></b>
The address that is looked up instead of the null
sender address.
<b><a href="postconf.5.html#parent_domain_matches_subdomains">parent_domain_matches_subdomains</a></b>
List of Postfix features that use <i>domain.tld</i> pat-
terns to match <i>sub.domain.tld</i> (as opposed to
requiring <i>.domain.tld</i> patterns).
<b><a href="postconf.5.html#transport_maps">transport_maps</a></b>
List of transport lookup tables.
<b>SEE ALSO</b><a href="trivial-rewrite.8.html">trivial-rewrite(8)</a>, rewrite and resolve addresses
<a href="master.5.html">master(5)</a>, <a href="master.5.html">master.cf</a> file format
<a href="postconf.5.html">postconf(5)</a>, configuration parameters
<a href="postmap.1.html">postmap(1)</a>, Postfix lookup table manager
<b>README FILES</b><a href="ADDRESS_REWRITING_README.html">ADDRESS_REWRITING_README</a>, address rewriting guide
<a href="DATABASE_README.html">DATABASE_README</a>, Postfix lookup table overview
<a href="FILTER_README.html">FILTER_README</a>, external content filter
<b>LICENSE</b>
The Secure Mailer license must be distributed with this
software.
<b>AUTHOR(S)</b>
Wietse Venema
IBM T.J. Watson Research
P.O. Box 704
Yorktown Heights, NY 10598, USA
TRANSPORT(5)
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